One year ago, a municipality banned

Answer choices

1. A

   No Impact2% picked this

   Why did many residents continue to use detergents

   We don't care about people who are still using phosphate detergents. We're trying to ascertain whether any residents stopped using phosphate detergents. So interviewing the people who still use detergents won't help us at all.

   2%
2. B

   No Impact: phosphate-free2% picked this

   What pollutants, if any, are present in phosphate-free

   We're trying to ascertain what caused the treatment plant's phosphate pollution to go down. Phosphate-free detergents don't contribute to "phosphate pollution", so who cares what other sort of pollutants they may have? We are investigating whether anyone switched to phosphate-free detergents. Telling us the ingredients of those detergents doesn't help us figure out whether anyone switched to using them.

   2%
3. C

   Correct74% picked this

   Were any changes made in the past year to the way the municipality’s wastewater treatment

   Why this is right

   This does what Weaken answers most typically do on Curious Fact / Explanation arguments -- it suggests an alternate explanation for the curious fact. Why did phosphate pollution from the treatment plant decrease this past year? The author is assuming it must be because some residents switched to phosphate-free detergent (so there was less phosphate going into the treatment plant). But she's failing to consider Alternate Explanations: what if the phosphate pollution decreased instead because they just installed better equipment or processes at the treatment plant?

   Skill tested: Evaluate · how this choice captures the argument's function is the move to repeat next time.

   74%
4. D

   Irrelevant: where the water goes next21% picked this

   Does most of the phosphate pollution in the municipality’s waterways come from treated wastewater from

   We're trying to figure out why less phosphate pollution came out of the plant last year. This answer is about where the water goes after it's come out of the plant, and whether it ends up being a significant source of something somewhere else. All that matters to this question is solving the causal mystery of why less phosphate pollution came out of the treatment plant. Is it because less phosphate entered the treatment plant? If so, why did less enter? Or is it because the treatment plant removed more phosphate while the wastewater was inside the plant? Once this water exits the plant and we measure the plant's output of phosphate as lower than before, we're done with caring about it.

   21%
5. E

   Weak Impact2% picked this

   Did municipal officials try to stop people from bringing detergents containing phosphates

   If officials did try to stop people from bringing detergents w/ phosphates into the municipality, then that would mildly strengthen the plausibility that some residents probably switched to phosphate-free detergents. But if we say, "No, officials didn't try to stop people from bringing illegal detergents into the city", it doesn't weaken. It's perfectly plausible that some residents might switch to phosphate-free detergents, given that one year ago the phosphate-variety was banned, with or without official trying to stop rulebreakers from crossing the border with their contraband detergent. The objection we get from (C) is that, "the treatment plant is emitting less phosphate because they improved their filtering processes this year, not because residents switched to phosphate-free." The objection we would get from (E) is that, "it's not plausible that some residents switched to phosphate-free detergents, because the city officials didn't try to stop people from bringing phosphate detergents into the city."

   2%